• Journal of Environmental Health Sciences
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• v.26 no.4
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• pp.58-64
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• 2000

Indoor air quality tends to be the dominant contributor to personal exposure, because most people spend over 80% of their time indoors. In this study, indoor and outdoor NO$_2$ concentrations were measured and compared with simultaneously personal exposures of 21 university students in weekday and weekend. House characteristics and activity pattern were used to determine the impacts of these factors on personal exposure. Since university students spent most of their times in indoor, their NO$_2$ exposure was associated with indoor NO$_2$ level rather than outdoor NO$_2$ level both weekday and weekend in spite of different time activity. Using time-weighted average model, NO$_2$ exposures of university students were estimated by NO$_2$ measurements in indoor home, indoor school, and outdoor home levels. Estimated NO$_2$ personal exposures were significantly correlated with measured NO$_2$ personal exposures($r^2$=0.87). However, estimated personal NO$_2$ exposures by time-weighted average model were underestimated, comparing with the measured personal NO$_2$ exposure. Using multiple regression analysis, effect of personal NO$_2$ exposure for transportation was confirmed.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.8 no.5
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• pp.1-9
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• 2005

This study was conducted to investigate the effect of aquatic plant as a botanical air purification on the indoor air pollution by formaldehyde. Three aquatic plants such as Eichhornia crassipes, Cyperus alternifolius, Echinodorus cordifolius, were selected for this study and they were placed in the artificially contaminated chamber under laboratory condition. The results showed that all three plants could remove the formaldehyde from the contaminated air system effectively. Reduction in the formaldehyde levels by Eichhornia crassipes, which is the floating plant, might be associated with the factors of plant and water. Reduction in the formaldehyde levels by Cyperus helferi and Echinodorus cordifolius, which were emergent plant, was due to the complex effect of plant, soil medium and water. In aquatic plant system, dissolution, microbial degradation in rhizosphere, uptake through root and shoot, sorption to soil and shoot, hydrolysis are known as the main mechanisms of water soluble pollutants in the given system. The advantages of indoor air quality control system using aquatic plants can be; 1) various purifying mechanisms than foliage plants, 2) effective for decontamination of water soluble pollutants; 3) easy for maintenance; 4) diverse application potential. Therefore it was suggested from the results that indoor air control system of aquatic plants should be more effective for reduction of indoor air pollutants.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.7
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• pp.521-530
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• 2009

This study has been made to execute a research in order to lead the improvement of indoor air quality, examining the indoor ventilation characteristics by using a numerical analysis method. To this end an extensive parametric investigation are made according to various external flow variables such as main wind direction and wind speed by season, building layout design, and location of ventilators, etc. in Daedeok Techno Valley, one of large-scaled apartment in Daejeon. It is observed there was a significant difference of main wind direction between summer and winter. The main wind direction in summer was a south wind, and on the contrary the direction in winter is northnorthwest, which is similar to the average main wind direction for 10 years. One of the important calculation results is that the change of wind direction causes a significant effect on the apartment ventilation by the change of pressure difference around each complex of apartment. In case of favorable area of ventilation, the indoor ventilation rate can meet 0.7 ACH from the standard value only with natural ventilation. On the contrary, in other area the value was much lower than the standard value. If the calculation result applies to the design of layout apartment or placement of ventilators, it will be greatly helpful to the energy saving because it can be parallel with the natural ventilation to help securing ventilation rate, not much depending on the mechanical ventilation.

• Journal of Environmental Health Sciences
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• v.37 no.3
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• pp.193-200
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• 2011

Objective: The purpose of this study is to compare and analyze the level of exposure to volatile organic compounds for different kinds of households in apartments or houses and analyze the relation between atopy-related symptoms and concentration of volatile organic compounds in order to improve indoor air quality and start to build a process to prevent environmental diseases. Method: From July 2010 to November 2010, TVOC concentration levels were measured and analyzed in 402 general households and 236 weak households, totalling 638 households. Residents were asked to fill out a survey on environmental disease. All resources were analyzed using SPSS 12.0 program. Result: In comparing the differences in concentration levels of volatile organic compounds for different types of households, including existing apartments and houses, the type of housing did not affect the concentration level of volatile organic compounds, but the relevance with skin trouble, diagnosed atopy, and atopy systems all had statistical similarities. Moreover, above-limit volatile organic compounds showed statistical relevance with amount of ventilation, time of construction, skin trouble, diagnosed atopy and atopy symptoms. Conclusion: The study concludes that as the time of construction recedes further into the past and as the amount of ventilation is higher, the exposure level to volatile organic compounds was lower and the group that were suffering from atopy symptoms had higher exposure to volatile organic compounds.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2008.04a
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• pp.176-177
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• 2008

• IEMEK Journal of Embedded Systems and Applications
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• v.17 no.1
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• pp.9-17
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• 2022

As the COVID-19 pandemic situation worsens, the time spent indoors increases, and the exposure to indoor environmental pollution such as indoor air pollution and noise also increases, causing problems such as deterioration of human health, stress, and discord between neighbors. This paper designs and implements a system that measures and monitors indoor air quality and noise, which are representative evaluation criteria of the indoor environment. The system proposed in this paper consists of a particulate matter measurement subsystem that measures and corrects the concentration of particulate matters to monitor indoor air quality, and a noise measurement subsystem that detects changes in sound and converts it to a sound pressure level. The concentration of indoor particulate matters is measured using a laser-based light scattering method, and an error caused by temperature and humidity is compensated in this paper. For indoor noise measurement, the voltage measured through a microphone is basically measured, Fourier transform is performed to classify it by frequency, and then A-weighting is performed to correct loudness equality. Then, the RMS value is obtained, high-frequency noise is removed by performing time-weighting, and then SPL is obtained. Finally, the equivalent noise level for 1 minute and 5 minutes are calculated to show the indoor noise level. In order to classify noise into direct impact sound and air transmission noise, a piezo vibration sensors is mounted to determine the presence or absence of direct impact transmitted through the wall. For performance evaluation, the error of particulate matter measurement is analyzed through TSI's AM510 instrument. and compare the noise error with CEM's noise measurement system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.12
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• pp.6610-6617
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• 2013

This study examined the current and future Indoor Air Quality (IAQ) control device markets and analyzed the recent studies on indoor air pollutantr emoval to develop a new technology for fine dust control. Currently, the mechanical filter technique occupies the bulk of the IAQ control market but the electronic technique is emerging as an alternative to control fine dust efficiently. Among the gaseous VOCs and fine dust particles contaminating the indoor air quality, fine dust particles are more problematic because they threaten human health by penetrating deep into the body and producing secondary contaminants by chemical reaction with VOCs. The electronic IAQ control device using dielectrophoretic and electrostatic forces is a good option for public spaces where many people pass, and at the same time, it needs to consider temperature, humidity, and the particle properties of specific areas to highlight the control efficiency. Electronic-related technology is expected to be used widely in many public/private spaces wherever a dust-free environment is required.

• Journal of Environmental Science International
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• v.16 no.9
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• pp.1019-1026
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• 2007

This study was performed in 30 selected apartments in Seoul, Asan and Daegu area which were constructed within 4 years and over 4 years, to measure the concentration of VOCs(benzene, toluene, xylene) from July, 2004 to September. Mean ratios of indoor to outdoor VOCs concentrations in the construction under 4 years were higher in 1 than average, I/O ratio of over 4 years were lower in 1. This was considered that the VOCs density influences indoor pollutant. For the indoor air quality estimation, the deposition constant and the source strength factor of toluene were $1.49{\pm}2.05\;hr^{-1}\;and\;36.95{\pm}52.26\;ppb/h$, respectively.

• Journal of Environmental Health Sciences
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• v.43 no.6
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• pp.509-515
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• 2017

Objectives: The purpose of this study was to assess the indoor levels of $PM_{10}$, VOCs and aldehydes in nail shop and hair salon. Methods: The field survey was conducted for 52 hair salons 52 nail shops, and 26 shop-in-shops in Seoul and Daegu city. The field technicians investigated characteristics of each shop including operating time, indoor volume, ventilation and so on. Indoor concentrations of $PM_{10}$, VOCs and aldehydes, indoor temperature and humidity were measured in 12 hair salons, 12 nail shops and 6 shop-in shops. MP Surveryor II (Graywolf, USA) was used to measure $CO_2$ concentration, temperature and humidity for 8 hours. $PM_{10}$ concentrations were measured by minivolume air sampler with Teflon quartz filter ($0.2{\mu}m$ pore size, ${\varphi}$ 47 mm, Graseby-Anderson TEF-DISKTM) for 6 hours. VOCs passive sampler (OVM 3500) was used to collect VOCs for 8 hours and analyzed by GC/MSD. Results: The $CO_2$ concentrations were $759.4{\pm}58.2$ ppm in nail shops, $731.0{\pm}72.5$ ppm in hair salons, and $656.4{\pm}31.2$ ppm in shop-in-shops. The $PM_{10}$ concentrations were $27.5{\pm}14.2{\mu}g/m^3$ in nail shops, $33.1{\pm}6.3{\mu}g/m^3$ in hair salons, and $39.0{\pm}26.9{\mu}g/m^3$ in shop-in-shops. TVOCs concentrations were $3085.4{\pm}1667.8{\mu}g/m^3$ in nail shops, $2131.1{\pm}617.3{\mu}g/m^3$ in hair salons, and $1550.3{\pm}529.0{\mu}g/m^3$ in shop-in-shops. TVOCs concentrations in nail shops were significantly higher than those in hair salons and shop-in-shops (p=0.002). Formaldehyde concentrations were $60.8{\pm}36.6{\mu}g/m^3$ in nail shops, $89.1{\pm}55.4{\mu}g/m^3$ in hair salons, and $45.1{\pm}22.5{\mu}g/m^3$ in shop-in-shops. Conclusion: TVOCs concentrations in nail shop were the highest among others. TVOC concentrations in all stores exceeded indoor air quality stand of indoor air quality control in public-use facilities, etc act.

• Journal of Environmental Health Sciences
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• v.33 no.4
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• pp.242-249
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• 2007

Indoor air quality has become a topic of interest and concern. Especially changes in construction design and the increased use of synthetic products may result in an increasing of complaints and health effects about the quality of indoor air at home. In this study, nitrogen dioxide($NO_2$) and volatile organic compounds(VOCs) within new and established apartments on the basis of 4 years of building year were measured every 3 days consecutively during 60 days. We selected each 10 house in Seoul, Asan and Daegu, respectively, and produced risk numbers for hazard quotients, and predicted increases in incidence of cancer. The calculations were made for the adult with default exposure values and also made for a worst case scenario using Monte-Carlo simulation as describing the reasonable exposure(RME). Mean of Monte carlo analysis by benzene, in the construction under 4 years (male: $9.2{\times}10^{-5}$, female: $1.0{\times}10^{-4}$) and over 4 years (male: $6.8{\times}10^{-5}$, female: $8.3{\times}10^{-5}$) exceeded $10^{-6}$ of permitted standards in US EPA, RME of Monte carlo analysis. In construction under 4 yews (male: $9.9{\times}10^{-3}$, female: $9.6{\times}10^{-3}$) and over 4 years (male: $9.8{\times}10^{-3}$, female: $7.8{\times}10^{-3}$) exceeded $10^{-4}$ of maximum permitted standards in US EPA. The hazard index of non-carcinogenic pollutants by nitrogen dioxide, toluene, m,p-xylene and o-xylene, both male and female in apartment constructed under 4 yews and over 4 years was found less than the permitted standards of hazardous health effects in CTE. Significant cancer risks and non-cancer hazard quotients were predicted in under 4 yews of building year.